Simply removing the rev limiter, without making any other modifications to a car, will do next to nothing. In some cases, being able to rev the engine higher will yield slightly better performance, often at the cost of more engine wear.
The stock exhaust really restricts everything, so don't even think about removing the rev limiter if you're still running the stock exhaust. The stock camshaft is designed to make power in the stock rev range, so there really isn't any reason to raise the rev limiter if you still have the stock camshaft installed. About the only reason I see to raise it when you're still running with the stock camshaft would be so you don't accidentally hit it (when, driving competitively on the street, or in another similar situation). Once you install a sport camshaft you will want to raise the rev limiter so you can use the power the camshaft makes above 6000 RPM. You should also give the engine some more fuel and richen up the mixture a bit if running a sport camshaft, and if running in the high RPMs. (Read this about getting more fuel to the engine.)
If you're worried about running your car to some really high RPMs, don't. Unless you build an all-out race car, you will not be reving past 7000-8000 RPM. Any car that makes good power above 7000 makes little power below 4000-5000 RPM, and is not by any means a street car. Phillip's 16v race Fox was built to be able to rev up to about 10,000 RPM, but he doesn't need to go past 8000 on the track.
If you check Techtonics
Tuning's Camshaft Specs
page, you will see that even their race camshafts do not make power
above 7500 RPM. So even if you go crazy with the camshaft, you won't
be revving your engine to ridiculous heights.
[Note: I have no affiliation with Techtonics, other than using some of their parts in my cars.]
The only options on Digifant Foxes would be to: